Neuronal ensemble control of prosthetic devices by a human with tetraplegia. Nature

Department of Neurology, Massachusetts General Hospital, Brigham and Women's Hospital, and Spaulding Rehabilitation Hospital, Harvard Medical School, 55 Fruit Street, Boston, Massachusetts 02114, USA.
Nature (Impact Factor: 41.46). 08/2006; 442(7099):164-71. DOI: 10.1038/nature04970
Source: PubMed


Neuromotor prostheses (NMPs) aim to replace or restore lost motor functions in paralysed humans by routeing movement-related signals from the brain, around damaged parts of the nervous system, to external effectors. To translate preclinical results from intact animals to a clinically useful NMP, movement signals must persist in cortex after spinal cord injury and be engaged by movement intent when sensory inputs and limb movement are long absent. Furthermore, NMPs would require that intention-driven neuronal activity be converted into a control signal that enables useful tasks. Here we show initial results for a tetraplegic human (MN) using a pilot NMP. Neuronal ensemble activity recorded through a 96-microelectrode array implanted in primary motor cortex demonstrated that intended hand motion modulates cortical spiking patterns three years after spinal cord injury. Decoders were created, providing a 'neural cursor' with which MN opened simulated e-mail and operated devices such as a television, even while conversing. Furthermore, MN used neural control to open and close a prosthetic hand, and perform rudimentary actions with a multi-jointed robotic arm. These early results suggest that NMPs based upon intracortical neuronal ensemble spiking activity could provide a valuable new neurotechnology to restore independence for humans with paralysis.

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Available from: Gerhard M Friehs, Oct 05, 2015
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    • "The first strategy aims at bypassing nonfunctional cortico-spinal pathways to allow for continuous and permanent control of robotic devices (Collinger et al., 2013) or functional electric stimulation (FES) of paralyzed muscles (Moritz et al., 2008; Pohlmeyer et al., 2009; Ethier et al., 2012; McGie et al., in press; Pfurtscheller et al., 2003). By substituting for lost motor functions, such assistive BMIs have demonstrated recovery of versatile motor control in daily life activities (Hochberg et al., 2006; Collinger et al., 2013). The second strategy aims at facilitation of neuroplasticity and motor learning to enhance motor recovery (rehabilitative BMIs) (Dobkin, 2007; Soekadar et al., 2011a) (Fig. 1a). "
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    • "Thanks to technological progress based on non-invasive EEG and invasive intracortical recording (Hochberg et al., 2006; Aflalo et al., 2015), people may be capable of using brain activity to control BCI devices (Birbaumer et al., 1999) and to move a prosthetic or robotic limb. Most of the current BCI systems are based on at least two main cognitive and brain processes. "
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    ABSTRACT: Acting efficiently in the world depends on the activity of motor and somatosensory systems, the integration of which is necessary for the proper functioning of the sensorimotor loop (SL). Profound alterations of SL functioning follow spinal cord injury (SCI), a condition that brings about a disconnection of the body from the brain. Such disconnection creates a substantial deprivation of somatosensorial inputs and motor outputs. Consequent somatic deficits and motor paralysis affect the body below the lesion level. A complete restoration of normal functions of the SL cannot be expected until basic neuroscience has found a way to re-establish the interrupted neural connectivity. Meanwhile, studies should focus on the development of technical solutions for dealing with the disruption of the sensorimotor loop. This review discusses the structural and functional adaptive reorganization of the brain after SCI, and the maladaptive mechanisms that impact on the processing of body related information, which alter motor imagery strategies and EEG signals. Studies that show how residual functions (e.g. face tactile sensitivity) may help people to restore a normal body image are also reviewed. Finally, data on how brain and residual body signals may be used to improve brain computer interface systems is discussed in relation to the issue of how such systems may help SCI people to re-enter the world and interact with objects and other individuals.
    Neuropsychologia 06/2015; · 3.30 Impact Factor
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    • "Chronically implanted intracortical microelectrodes have been used in invasive brain machine interfaces (BMI) for controlling computers and assistive devices to restore function after paralysis[1] [2] [3]. However, current devices suffer from recording instabilities that lead to loss of cells over time[4]. "
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    ABSTRACT: Current microelectrodes designed to record chronic neural activity suffer from recording instabilities due to the modulus mismatch between the electrode materials and the brain. We sought to address this by microfabricating a novel flexible neural probe. Our probe was fabricated from parylene-C with a WTi metal, using contact photolithography and reactive ion etching, with three design features to address this modulus mismatch: a sinusoidal shaft, a rounded tip and a polyimide anchoring ball. The anchor restricts movement of the electrode recording sites and the shaft accommodates the brain motion. We successfully patterned thick metal and parylene-C layers, with a reliable device release process leading to high functional yield and were able to sample stable neural activity for over 2 years with this probe. We have successfully optimized the fabrication process to produce a reliable probe with high functional yield. This novel reliably microfabricated probe can record stable neural activity for up to two years without delamination, surpassing the current state-of-the-art intracortical probes used for chronic extracellular recording.
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